The present invention relates to devices designed to measure a magnetic field. Devices of this kind, also known as magnetometers, are used in particular to prepare charts of the earth's magnetic field in the course of geological prospecting operations.
It is known to measure magnetic fields using various physical effects of the field. For example, the electromotive force induced by the field in a rotating coil, can be measured. However, to achieve adequate sensitivity and accuracy, it is necessary to employ methods which involve a considerable amount of very delicate equipment. Thus, the most recent method to be used consists in measuring the resonance frequency of the protons in a material such as hydrogen, immersed in the field to be measured.